Chen X, et al. - In this study of 21 eyes from 15 preterm infants with clinically diagnosed stage 4 retinopathy of prematurity (ROP), experts examined optical coherence tomography (OCT) characteristics of eyes with stage 4 ROP and contrasted them with indirect ophthalmoscopy findings and grading of photographs. To ascertain foveal involvement and distinguish retinal detachment and retinoschisis, handheld OCT imaging was beneficial in the clinical assessment of stage 4 ROP. Several infants diagnosed with stage 4A ROP had retinoschisis without OCT evidence of retinal detachment. This group of infants could designate a substage of stage 4A ROP, ie, stage 4A–schisis via OCT. Findings imply that in the clinical assessment of stage 4 ROP, handheld OCT imaging could be beneficial.